Non-adherence to treatment costs the NHS more than £500M each year. Adherence is especially important when treating patients with chronic conditions that require lifetime pharmacological treatment, such as schizophrenia, Parkinson’s disease, HIV and Alzheimer’s disease. In addition to the economic impact, there is a direct human cost, as non-compliance significantly reduces patients’ health-related quality of life and, in many cases, is associated with early death. Non-adherence to treatment for schizophrenic patients increases the risk of relapse, hospitalisation and suicide (relapse costs £15,000/year/patient). Moreover, Parkinson’s or Alzheimer’s disease patients that do not adhere to treatment have higher risk of institutionalisation or hospitalisation, costing a total of up to £194M/year. Considering the economic and human impact of non-adherence to treatment, there is a clear need for drug delivery systems capable of providing unattended drug administration for prolonged periods of time for these conditions. Therefore, this PhD project seeks to develop long-acting drug delivery systems (LADDS) using biodegradable polymers for treatment of chronic conditions. These polymers will be formulated into a range of innovative types of LADDS. Pharmaceutical companies, charities and UK Research Councils all currently have LADDS development as a priority. Indeed, the QUB Drug Delivery Team has received extensive funding to develop and apply such systems. The Supervisory Team has been supported by EPSRC, Academy of Medical Sciences, Prostate Cancer UK the US NIH and USAID. Moreover, a range of leading pharmaceutical companies are currently funding research projects in our lab to develop LADDS. Accordingly, QUB has extensive experience in developing such systems. The interest of pharmaceutical companies in LADDS have risen significantly. Accordingly, this project will address not only a clear patient need, but also a growing commercial interest. This 3-year PhD project will be focused on delivery of two representative compounds: risperidone and tizanidine. The first drug is an antipsychotic drug used for the treatment of schizophrenia. The second compound is a centrally acting muscle relaxant used to treat spasticity in multiple sclerosis. The project will explore the use of several technologies, including 3D-printing, to develop solid implantable LADDS.